During many percutaneous procedures, medical devices are inserted into a patient's vascular system and advanced through blood vessels to reach a desired location. Small amounts of air or other gas bubbles can be accidentally introduced into the vascular system during the procedure. For example, gas bubbles can enter the bloodstream as a catheter or other medical device is advanced through a patient access device, such as a vascular introducer sheath, resulting in gas bubbles (i.e. gas emboli) in the bloodstream. Gas bubbles that enter a vein can be captured or otherwise stopped within the lungs. However, if a gas bubble or collection of gas bubbles in the venous system is sufficiently large and becomes trapped in a chamber of the heart, blood flow in the heart can become compromised and can result in serious injury and even death.
One or more gas emboli within an artery, termed arterial gas embolism (AGE), often lead to more serious consequences than gas bubbles in a vein, such as when a gas bubble in an artery stops blood flow to a tissue area fed by the artery. The consequences of ‘AGE’ depend on the area deprived of blood flow, and can include stroke, if the brain is affected, or a heart attack, if the heart is affected.
Typically, patient access devices, such as vascular introducer sheaths, are used during clinical therapeutic and diagnostic procedures to facilitate insertion and exchange of catheters or other medical devices into a patients' vascular system. The introducer sheaths are tubes inserted into patients' vascular systems to act as guides for the catheters or other medical devices. Once the distal end of the introducer sheath is inserted into a patients' vascular system, the proximal end of the sheath remains outside the patient for the introduction of catheters or other medical devices.
When a catheter or other medical device is inserted into the proximal end of the sheath, air or other gas may be carried into the sheath with the catheter or other medical device, and passed into the patients' vascular system. As discussed above, this gas may form gas emboli when entering the blood stream, preventing normal blood flow to the heart, brain or other body location, and potentially causing tissue damage or even death of the patient. If a first device needs to be replaced with a second device, the first device is withdrawn from the sheath and the second device is then inserted into the sheath, including an additional risk of introducing gas into the patient's vascular system. If the devices used in treating the patient must be exchanged frequently via the sheath, the chance of gas introduction into the patients' vascular system is further increased.
Since typical introducer sheaths and other patient access devices do not prevent introduction of gas into the patient's bloodstream along with the catheter or other medical device being inserted, clinicians are required to manually prevent such an occurrence. Therefore, there is a need for improved patient access devices and methods of device introduction to prevent or reduce the introduction of gas bubbles into the patient's bloodstream to avoid the complications discussed above.